 /*******************************************************************************
  * Copyright (c) 2006, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.ide.undo;

 import java.io.ByteArrayInputStream ;
 import java.io.InputStream ;
 import java.net.URI ;

 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.ui.internal.ide.undo.ContainerDescription;
 import org.eclipse.ui.internal.ide.undo.FileDescription;
 import org.eclipse.ui.internal.ide.undo.IFileContentDescription;

 /**
  * A CreateFileOperation represents an undoable operation for creating a file in
  * the workspace. If a link location is specified, the folder is considered to
  * be linked to the file at the specified location. If a link location is not
  * specified, the file will be created in the location specified by the handle,
  * and the entire containment path of the file will be created if it does not
  * exist. Clients may call the public API from a background thread.
  *
  * This class is intended to be instantiated and used by clients. It is not
  * intended to be subclassed by clients.
  *
  * @since 3.3
  *
  */
 public class CreateFileOperation extends AbstractCreateResourcesOperation {

     /**
      * Create a CreateFileOperation
      *
      * @param fileHandle
      * the file to be created
      * @param linkLocation
      * the location of the file if it is to be linked
      * @param contents
      * the initial contents of the file, or null if there is to be no
      * contents
      * @param label
      * the label of the operation
      */
     public CreateFileOperation(IFile fileHandle, URI linkLocation,
             InputStream contents, String label) {
         super(null, label);
         ResourceDescription resourceDescription;
         if (fileHandle.getParent().exists()) {
             resourceDescription = new FileDescription(fileHandle, linkLocation,
                     createFileContentDescription(fileHandle, contents));
         } else {
             // must first ensure descriptions for the parent folders are
 // created
 ContainerDescription containerDescription = ContainerDescription
                     .fromContainer(fileHandle.getParent());
             containerDescription.getFirstLeafFolder()
                     .addMember(
                             new FileDescription(fileHandle, linkLocation,
                                     createFileContentDescription(fileHandle,
                                             contents)));
             resourceDescription = containerDescription;
         }
         setResourceDescriptions(new ResourceDescription[] { resourceDescription });

     }

     /*
      * Create a file state that represents the desired contents and attributes
      * of the file to be created. Used to mimic file history when a resource is
      * first created.
      */
     private IFileContentDescription createFileContentDescription(
             final IFile file, final InputStream contents) {
         return new IFileContentDescription() {
             /*
              * (non-Javadoc)
              *
              * @see org.eclipse.ui.internal.ide.undo.IFileContentDescription#getContents()
              */
             public InputStream getContents() {
                 if (contents != null) {
                     return contents;
                 }
                 return new ByteArrayInputStream (new byte[0]);
             }

             /*
              * (non-Javadoc)
              *
              * @see org.eclipse.ui.internal.ide.undo.IFileContentDescription#getCharset()
              */
             public String getCharset() {
                 try {
                     return file.getCharset(false);
                 } catch (CoreException e) {
                     return null;
                 }
             }

             /*
              * (non-Javadoc)
              *
              * @see org.eclipse.ui.internal.ide.undo.IFileContentDescription#exists()
              */
             public boolean exists() {
                 return true;
             }
         };
     }
 }

